Draft regulator for orchard heaters



Feb. 15, 1944.

w. cfscHEu DRAFT REGULATOR FOR ORCHARD HEATERS Filed Dec. 18, 1940INVENTOR: WLLIAM C. SCHEU,

ATTORNEY.

Patented Feb 15, 1944 DRAFT REGULATOR FOR ORCHARD HEATERS William C.Scheu, Upland, Calif.;

Henrietta Scheu, W. Leland Scheu, and C. H. Dekker, executors of saidWilliam C. Scheu, deceased, assignors to Scheu Products Company, Ltd., acorporation of California Application December 18, 1940, Serial No.370,615

1 Claim.

This invention relates to temperature-controlled draft regulators forliquid fuel orchard heaters and is concerned particularly with heatresponsive devices for automatically establishing a controlled influx ofcombustion air to the fuel vaporizing chamber of such a heater fornormal burning operation thereof following the starting or ignitionperiod of such a heater.

Without being necessarily limited thereto, the heat-responsivedraft-regulating device of this invention is primarily adapted for usewith Vaporizing type liquid fuel orchard heaters. In heaters of thistype a vaporizing flame is maintained at or near the surface of the bodyof fuel contained in the heater to cause vaporization from the surfaceof this fuel. The oil'vapors pass upwardly into a stack where additionalair is mixed with them to cause substantially complete combustion of thevapors in a main flame at a point removed from the vaporizing flame.

A heater of this general type provided with such a stack forming a maincombustion chamber is shown in my U. S. Patent No. 1,930,863, issuedOctober 17, 1933.

Heaters of this type are provided with one or more air-admittingopenings in the body communicating with the vaporizing chamber to admitair to the vaporizing flame in the vaporizing chamber. able to supply arelatively large quantity of air to the vaporizing chamber to supportthe vaporizing fiamewhen the heater is first ignited and until thevaporizing chamber has been heated. After the vaporizing chamber hasbecome heated and the main combustion flame is well established, asmaller amount of heat from the vaporizing flame is required to vaporizefuel; and if the air supply is not reduced to diminish the flame, therewill be a tendency to vaporize an excess quantity of fuel. Theserelations are all a function of the heat generated in the vaporizingchamber and are substantially independent of the temperatures existingwhere the main combustion takes place in the stack, or at any otherplace removed fromthe vaporizing flame.

In order to obtain proper and satisfactory operation of such a liquidfuel heater it is desirable to restrict the flow of air admitted to thevaporizing chamber after a sufficient quantity of heat has beengenerated therein. In many an excess quantity of fuel and often smokesbadly, thus wasting fuel.

With such arrangement it is prefer- The principal object of theinvention is to provide a heat-controlled draft-regulating device foruse in connection with a vaporizing type of liquid fuel orchard heater,which is operable to provide a substantially unrestricted inflow of airinto the vaporizing chamber during a preliminary ignition period and torestrict automatically the admission of air to said vaporizing chamberwhen the ignition is completed, in response to atemperature increaseresulting from the heat generated within the heater, so as to thereaftermaintain the relatively restricted admission of air to the chamber inquantities suf' flcient to maintain the desired normal burning rateduring subsequent operation of the heater. I A further object of theinvention is to provide a heat-responsive draft-regulating device foruse in association with a vaporizing type liquid fuel orchard heater,which is rugged, simple in operation andconstruction, and which may bereadily removed for repair or for transfer to another heater where itmay be readily installed. I

Further objects and advantages of the invention, of which the above aretypical, will become apparent as the description proceeds.

The draft-regulating device of my invention may comprise a regulatingplate'adapted to be pivotally mounted adjacent the air-admitting openingof a liquid fuel orchard heater. The draft-regulating plate is movablebetween a first position affording relatively free passage of airthrough the opening and a second position re stricting the passage ofair through the opening. A bimetallic thermostatic element is providedwhich is operatively associated with the plate and is disposed inheat-receiving relation to the heater and is operable in response toheat generated in the heater to cause the plate to move from its firstposition to its second position.

How the above, as wellas other objects and advantages of my inventionare attained will be more readily understood by reference to thefollowing description and the annexed drawing, in which: I

Fig. 1 is a vertical section through the bowl of an orchard heatershowing my improved draftregulating plate mounted on the bowl cover;

Fig. 2 is an enlarged fragmentary vertical section on line 2-2 of Fig.1, showing the draftregulating cap open in full lines and closed indot-dash lines; and

Fig. 3 is a fragmentary vertical section on line 33 of Fig.2.

There is shown in Figs. 1 to 3 of the drawing a portion of a standardtype of vaporizing liquid fuel orchard heater, indicated generally atID. The orchard heater comprises a bowl H which not only provides a basefor supporting the upper structure but also forms a reservoir thatcontain a body of liquid fuel I2 which is vaporized in bowl ll andburned in the heater stack. Bowl II is provided with a cover M which hasa centrally disposed collar portion Ma around which the lower end ofstack l5 fits snugly. The stack may be of any type suitable for orchardheaters, the exact kind being immaterial as far as the present inventionis concerned.

The space l6 above the fuel body l2 and enclosed by the walls of bowl IIand cover l4 constitutes a vaporizing chamber. A suitable openingdefined by the raised collar portion I! of cover I4 is provided in orderto admit air to the vaporizing chamber for maintenance of the vaporizingflame therein. A draft tube or flamestabilizing baffle I8 is preferablyprovided to facilitate the maintenance of a vaporizing flame withinchamber It. The upper end of draft tube I8 is preferably provided withan outwardly extending flange which engages the inwardly turned flangeon raised collar H, as shown in Fig. 3, to support the draft tube, whichextends downwardly from cover l4 into the oil body 12 as illustrated inFig. 1. The upper end 29 of draft tube I8 is open for the admission ofair which enters the vaporizing chamber through the draft tube. Asuitable wick I9 is preferably provided adjacent the upper end of tube!8, the wick member taking any suitable form, such as the bodyindicated, and is preferably of fibrous asbestos or other porousmaterial. The wick is preferably wrapped or enclosed in a foraminousmetal envelope, not shown, which holds the wick in place and yet permitsaccess of oil to the lower portion of the wick.

The draft-regulating device is shown as comprising a draft-regulatingplate 94 pivotally mounted on the cover l4 of the heater adjacent theair-admitting opening defined by the raised collar l1 and draft tube I8,as bymeans o-f hinge 95. Plate 99 is movable about hinge 95 between thefirst, or air-admitting position, shown in Fig. 2 in full lines, and thesecond, or airrestricting position, shown in Fig. 2 in dot-dash lines.The plate in moving between the first and second position passes throughan intermediate position in which the center of gravity of the assemblyis in a vertical plane passing through the hinge axis; and the plate isgravity biased toward the first position when it is between the firstand intermediate positions, and is gravity biased toward the secondposition when the second and intermediate positions.

A portion of said plate, such as a tab member 99, extends away from saidhinge and is so positioned as to be engageable by a pin member 99 and soformed as to have its outer end 9'! rest aga nst the cover M asindicated in full lines in Fig. 2.

The pin member 99 extends upwardly above the cover I9 through a suitableslot or opening 599 provided therein. The pin member is rigidly securedto a bimetallic thermostat bar 9| mounted in a suitable case 92 securedto the underside of cover M of the heater in any suitable manner, as bybolts 93.

The center of gravity of the assembly comprising regulating plate 94.the tab member 96 and associated parts adapted to swing about the hinge95. is to the left, as viewed in Fig. 2, of a vertical line extendingthrough the axis of hinge when the outer end 91 of tab member 96 is inengagement with the cover [4, so that a tilted position of the platemember for providing substantially free access of air to the heater maybe maintained by the action of gravity.

The plate 94 is preferably provided with one or'more air-admittingopenings 98, and an adjustable disk 99, provided with an adjustinghandle I92, is preferably mounted on plate 94. The disk 99 is preferablyrotatably mounted on the plate 94 at the center thereof, as through theagency of a spring-tensioned loose rivet I93 or the like. Disk 99 has aslot or opening I9] which is movable into and out of registration withthe openings 98, through the agency of the handle member I92, in orderto cover more or less of the openings 98 and so impose more or lessrestriction on air passing through openings 99 to the heater interiorwhen the plate 94 is lowered, as shown by dot-dash lines in Fig. 2.

When a heater provided with this embodiment of the device is lighted,the thermostat is cold and the thermostat and the openeddraft-regulating plate occupy positions shown in full lines in Figs. 2and 3. After the heater has been ignited, the flame from the vaporizingchamber plays against or radiates heat to the case 92 and the containedthermostat 9! gradually rises in temperature and bends upwardly.Movement of bimetallic element 9! causes pin 99 to engage and raise tabmember 96, tipping the plate mem ber 94 forward about the "hinge 95until the center of gravity of the plate and associated parts is movedto the right of the aforesaid vertical line. The plate member is thenbiased toward a draft-regulating position by gravity, independently offurther movement of the pin member 99, and falls freely down to itssecond or draftregulating position as is indicated in dot-dash linesinFig. 2 and in full lines in Fig. 1. The draft regulating plate 94 may beformed as a capshaped member so that the outer .edges of said cap mayengage the shoulders I! when said plate is in draft regulating positionas above described.

Upon being moved to and through the intermediate position the gravitybias toward the second position allows the plate to fall freely with theaid of gravity to the second position restricting the passage of airthrough the opening.

In its preferred form the plate is so proportioned that its center ofgravity is located above the pivotal or hinge axis and is shiftable bymovement of the plate between its first and second positions, from aposition in which a moment is produced urging the plate toward its firstposition to a position in which a moment is produced urging the platetoward its second position. The moments are such that when the plate isin the first or second position it is urged respectively toward thefirst and second positions. The action of the thermostatic element is tocause movement of the plate from the first position against this momentto a position in which the center of gravity has shifted sufiiciently toproduce sufficient moment to cause movement of the plate to the secondposition irrespective of further movement of the thermostatic element.

Having described my invention, it will be understood that variouschanges in the shape, construction, and arrangement of the various partsmay be made without departing from the spirit and scope of my invention;and consequently it is desired that the foregoing disclosure beconsidered as illustrative of, rather than limitative ment is producedurging the plate toward its position affording relatively free passageof air 10 through said opening and a second position restricting thepassage of air through said opening, the center of gravity of said platebeing located above the hinge and being shiftable by movement of saidplate from its first position toward its second position, from aposition in which a mofirst position to a position in which a moment isproduced urging said plate toward said second position, said plateincluding a portion extending outwardly from the plane thereof; abimetallic element carried on the underside of said cover and having anend adapted to move upwardly in response to heat; and a member securedto said end and extending through said cover, said member being adaptedto engage said portion when said plate is in its first position and movesaid plate'to shift its center of gravity to a position in which amoment is produced urging said plate toward its second position.

WILLIAM C. SCHEU.

